.DELTA..sup.16 -20-keto steroids have been converted to 16-substituted 20-keto steroids as is well known to those skilled in the art. More particularly, .DELTA..sup.16 -20-keto steroids have been converted to 16.alpha.-methyl-17.alpha.-hydroxy-20-keto steroids (U.S. Pat. Nos. 3,461,144) and 16.alpha.,17.alpha.-dihydroxy-20-keto steroids (U.S. Pat. Nos. 3,493,563 and 2,864,834 and J. Am. Chem. Soc. 78, 5693 (1956) and J. Am. Chem. Soc. 82, 3399 (1960)).
The transformation of a .DELTA..sup.5,16 -20-keto steroid to the corresponding 20-trimethylsilylenol ether by hydrosilylation is described in Helv. Chem. Acta 61, 3068 (1978).
The hydrosilylation of enones with silanes in the presence of tris-(triphenylphosphine)rhodium (I) chloride catalyst is known where there is 1,4-addition of the silane to the .alpha.,.beta.-unsaturated carboxy compound; see J. Organometallic Chemistry 94, 449 (1975).
The oxidation of non-steroid silylenol ethers to the corresponding .alpha.-hydroxy ketones is discussed in Tetrahedron Letters 4319 (1974).